Patent GB-190420941-A (GB)
Title: Railway Signalling Systems.
Inventor: PROKOV WILHELM
Filed: 1904-09-29
Granted: 1905-05-25
Abstract: 20,941. Prokov, W., and Richter, M. Sept. 29. Signalling-systems ; signalling-instruments ; contacts, electric ; semaphore signals ; interlocking ; indicators and repeaters, signal.- In a partly automatic and wholly electric system, electric traintreadles control the operation of special signalling - instruments, the mechanical semaphores being in connection with the instruments so that the semaphores and instruments are simultaneously actuated by the signalman. The electric treadle apparatus, Fig. 1, is contained within a case 1 fixed by bolts 4 to the track rail 9 between two sleepers, and depression of the rail by a passing train forces down a knifeedged plunger 5, which depresses a lever 10 pivoted at one end on a fixed adjustable knifeedge 23, and at the other end actuating a forked knife-edged rod 11, which similarly depresses a lever 12 pivoted on a fixed knife-edge. The lever 12 is pivotally attached to a vertical rod 14 with an upper wedge-shaped portion passing between a roller 18 on a fixed axis and a roller 16 on a movable axis eccentrically connected to a spindle 14. A weighted toothed sector 15 riding loosely on the spindle 14 is connected to it by a helical spring to minimize shocks, and gears with a pinion 29, which is provided with a friction clutch inactive during the upward movement of the sector 15, but on the downward motion causing the pinion 29 to rotate an escapement wheel 19 and actuate a pendulum 21 through an escapement. The vertical motion of the rod 13 due to the passage of a train thus rotates the sector 15, and causes an attached leaf spring 26 to pass upwards in contact with one side of an inclined contact-plate 27, while on the downward journey it passes on the opposite side of the contact-plate. According to which side of this plate 27 a metal contact-strip is affixed to, an electric circuit is closed by the first or last wheel of a train passing over the treadle, this circuit including wires 7, 7<1> connected to the metal contact-strip and the leaf spring 26. The pendulum 21 allows slow descent of the sector 15, the rod 13 descending by its own weight. In a modified form of contact, such as that between the leaf spring 26 and the plate 27, a rigid piece 26, Fig. 4, replaces the leaf spring and makes contact with one side of a flexible metal piece 131 in its upward motion, and with the other side in its downward motion. The piece 131 slides against coiled springs on two pins in an insulating-support, and the circuit wires are connected to one of the pins and to the piece 26, the flexible piece 131 being provided with an insulating-strip on one side. To obtain a greater motion of the plunger 5, Fig. 1, horizontal rods attached to the lugs 3 may connect the treadle apparatus to the track rail at two points further apart than the bolts 4. The combined signalling-instrument is shown in Fig. 9, while Fig. 12 shows the front portion of the instrument. The main shaft is operated manually in a clockwise direction only by a ratchet connection between the operating hand-crank and its shaft 33. A ratchet-wheel 42, Fig. 12, on the shaft 33 is regulated in its rotation by an escapement 80 and pendulum 81, and carries shaped metal contact-strips 91, 92 making contact with spring pins 83 .... 90 and 122 on a fixed insulating-plate 82, while red and white discs 44, 45 on the shaft 33 appear at a window in the case during the rotation. The shaft 33 is normally locked by the engagement of an attached lever 39, Fig. 9, provided with rollers 40, 41, against a locking-lever 60 pivoted on a spindle 59. When an electromagnet 64 is energized, attracting its armature 61 which releases the lever 60, the lever 39 and shaft 33 are released. A semicircular white disc 67 is then carried by an arm 66 attached to the lever 60 before the red disc 44 in the window, indicating that the shaft 33 may now be operated. This operation turns a cam 38 away from a projection on a lever 97, which is pivoted on a pin 98, and which thus falls, carrying an attached metal contact-plate 99 into contact with spring pins 94, 95, 96. The rotation of the lever 39 restores the lever 60 to its original locked position by engaging with surfaces 78, 79 upon it, thus raising the lever 60 until it is again held by the catch 61. When an electromagnet 57 is energized, its pivoted catch armature 54 releases a bell-crank lever 50 pivoted on a pin 47, and an attached arm 48 then carries a square coloured disc 49 before another window in the instrument case, the cam 38 being used to restore this lever 50 to its original raised position. A nose 101 on the lever 97 moves aside the catch armature 102 of an electromagnet 105 on being raised, and engages with this catch 102 on being released. The lowered lever 50 falls on a contact 58, completing a local circuit through a battery 135 and an alarm 136. A crank 34, Fig. 13, on the main shaft 33 of the signalling-instrument actuates the semaphore arm 75, which is thus positively raised into its ' safety ' position by an endless band 71 passing over guidepulleys 72, 73 to a crank disc 74, which actuates the arm 75 through a connecting-rod 76, a weighted lever 69 being employed to restore the arm 75 to the horizontal 'danger' position. A normally locked folding lever 68 connects the crank 34 with the arm 69 to be used for emergency signalling. Fig. 16 shows diagrammatically the connections in the signal system with signal cabins W, X, Y, each provided with a signalling-instrument d, a semaphore e, and two electric train-treadles a, b conveniently near together. Trains pass from left to right only, and the instrument d at W at present indicates line clear' with a white disc in front of the window, the instrument d' at X still indicates 'danger,' but the red disc at the window is covered by the white semicircular disc, indicating that a train may be accepted, while the instrument d<2> at Y indicates ' line blocked,' the section beyond Y being occupied. A train now passing over the treadle a at W closes the treadle contacts, but does not complete a circuit through the magnet 105, the spring contacts 94, 96 being disconnected. When the last train wheel passes over the treadle b, closing its contacts, a circuit is completed through the magnet 64, releasing the locking-lever 60, Fig. 9, and allowing the shaft 33 to be rotated manually to place the semaphore e, Fig. 16, at ' danger.' This circuit is soon broken, as the treadle contacts b return to their normal position, but meanwhile the rotation of the shaft 33 has rotated the escapement wheel 42 in the instrument d, and its attached contact-plate now connects the contacts 86, 87, which close a circuit through the electromagnet 64 of the previous cabin, thus releasing the lever 60 there and bringing the white semicircular disc over the red disc in the window to indicate that the section up to W is clear. Further movement of the escapement wheel connects the contacts 86, 88, and the plate 92 also connects the contacts 83, 84. This closes a circuit through the magnet 57 at X and releases the bellcrank lever carrying the coloured square disc, which appears at its window, and also sounds an alarm in a local circuit calling upon the signalman at X to raise the semaphore e<1> to 'safety.' This being done, the square disc disappears from its window, and the apparatus at X is now in position exactly as shown with regard to W. If a train be still in the section XY, or if the semaphore e<1> be still at 'danger,' the instrument d' will be in relative position as shown, and, on a second train passing into the section over the treadle a', a circuit will be closed through the electromagnet 105, the contacts 94, 96 being now closed because the signal e<1> is still at 'danger.' The electromagnet 105 attracts its armature catch, which allows the lever carrying the contact-plate 99 to fall and connect the contacts 95, 96, which closes a local circuit containing an audible alarm f<1> for the engine-driver and the signalman. The batteries g, g<1>, g<2> at the cabins W, X, Y are consecutively opposed to one another to prevent a leakage current from passing into adjacent sections.